	/* 定位 */
	/* z,rel,fix,abs,top,left,bottom,right,tra */

	/* 基本组合 */

	.z {
		z-index: -1;
	}

	.z-9 {
		z-index: 9;
	}

	.z-99 {
		z-index: 99;
	}

	.z-999 {
		z-index: 999;
	}

	.z-9999 {
		z-index: 9999;
	}

	.z-99999 {
		z-index: 99999;
	}

	.rel {
		position: relative;
	}

	.abs {
		position: absolute;
	}

	.fix {
		position: fixed;
	}

	.top {
		top: 0;
	}

	.top-50 {
		top: 50%;
	}

	.top-100 {
		top: 100%;
	}

	.left {
		left: 0;
	}

	.left-50 {
		left: 50%;
	}

	.left-100 {
		left: 100%;
	}

	.bottom {
		bottom: 0;
	}

	.right {
		right: 0;
	}

	.tra {
		transform: translate(-50%, -50%);
	}

	.tra-x {
		transform: translateX(-50%);
	}

	.tra-y {
		transform: translateY(-50%);
	}

	.tra-3d {
		transform-style: preserve-3d;
	}

	/* 常用组合 */

	.abs-x {
		position: absolute;
		left: 50%;
		transform: translateX(-50%);
	}

	.abs-y {
		position: absolute;
		top: 50%;
		transform: translateY(-50%);
	}

	.abs-cc {
		position: absolute;
		top: 50%;
		left: 50%;
		transform: translate(-50%, -50%);
	}

	.fix-x {
		position: fixed;
		left: 50%;
		transform: translateX(-50%);
	}

	.fix-y {
		position: fixed;
		top: 50%;
		transform: translateY(-50%);
	}

	.fix-cc {
		position: fixed;
		top: 50%;
		left: 50%;
		transform: translate(-50%, -50%);
	}